1. Field of the Invention
The present invention relates to an artificial hair to be implanted directly in the human skin, and particularly to an artificial hair with a function for inhibiting the proliferation of bacteria imparted to its hair root part, which is to be inserted into the human skin, and a portion of its hair shaft part, which is adjacent to the hair root part, and a preparation process and a preparation apparatus thereof.
2. Description of the Prior Art
It has been known to implant directly artificial hair, which is composed of a synthetic resin monofilament and have a hair root part at its end part, in the human skin.
It has also been proposed to cause a metal such as gold, silver or copper to adhere in the form of a thin film to the surface of such artificial hair by vacuum deposition so as to impart sterilizing effects thereto, thereby inhibiting the infection of bacteria and the purulence caused by bacteria upon hair implantation (see Japanese Patent Laid-Open No. 142704/1980).
However, gold is innoxious to human body but has no sterilizing and bacteriostatic effects. Copper has sterilizing and bacteriostatic effects but is noxious to human body. Both gold and copper are hence unsuitable for applying to the artificial hair with a view toward inhibiting the purulence caused by bacteria. Silver is innoxious to human body and also has the sterilizing and bacteriostatic effects.
The above known method is still insufficient for reasons as will be described below.
In the above known artificial hair, which has caused the metal such as gold, silver or copper to adhere in the form of a thin film to the surface of its hair root part by vacuum deposition, it appears that the metal is deposited under the conventional vacuum deposition conditions, namely, a vacuum degree of 10.sup.-7 Torr or higher and a surface temperature of an artificial hair to be deposited, i.e., a substrate temperature, of 60.degree.-80.degree. C. In this case, the metal 11 deposited forms a uniform layer in a crystalline state on the entire surface of the artificial hair 10 as illustrated as a conventional example by FIG. 8.
Here, the vacuum deposition, which has generally been performed, is described in further detail. In the conventional vacuum deposition apparatus 20, a vacuum vessel 21 is mounted on a fixing frame 35, which is fixed on a base stand 40, via a packing 34 as depicted in FIG. 9. An opening for an exhaust pipe 36 communicating with the vacuum vessel 21 is defined through the upper surface of the base stand 40. To the exhaust pipe 36, a vacuum pump 26 is connected through an oil trap 28, an oil diffusion pump 27, an exhaust conduit 41 and a three-way cock 29. In addition, a bypass line 42 branches off from the exhaust pipe 36 to be connected with the vacuum pump 26 through another three-way cock 30. On one hand, a crucible 23 equipped with a heater is attached to the fixing frame 35 by a crucible-supporting arm 31. In the vacuum vessel 21, a rotary body 22 adapted to fix a substance to be deposited is rotatably attached to a supporting arm 38 through a rotating shaft 37. A back heater 25 for heating the substance to be deposited is positioned on the side of the back surface of the rotary body 22.
Incidentally, reference numbers 24, 32, 33 and 43 are indicative of a shutter adapted to shade the flying of metal particles which evaporates, a driving chain for rotating the rotary body 22, a wire adapted to lift the vacuum vessel 21 and an electric wire for supplying electric power to the heater of the crucible 23, respectively.
In order to conduct vacuum deposition by means of this apparatus, the substance to be deposited is first of all attached on the rotary body 22, a depositing metal, for example, silver is placed in the crucible 23, the vacuum vessel is covered on, and the vacuum pump 26 is then driven to exhaust air in the vacuum vessel 21. At this time, the three-way cock 30 is opened first and the three-way cock 29 is turned on the side of the bypass line 42 to exhaust the air in the vacuum vessel 21 through the bypass line 42. When the vacuum degree of the vacuum vessel becomes about 10.sup.-5 Torr, the three-way cock 30 is closed and the three-way cock 29 is turned on the side of the oil diffusion pump 27. The oil diffusion pump 27 is then actuated. As the vacuum degree becomes 10.sup.-7 Torr or higher, the silver in the crucible 23 is heated to its melting temperature (961.9.degree. C.) or higher by the heater.
On one hand, the substance to be deposited, namely, a monofilament of a synthetic resin is heated by the back heater 25 to maintain the temperature of the substrate at 60.degree.-70.degree. C. (the temperature is different depending on the kind of a substance to be deposited).
Since particles of the silver start to discharge as the silver melts, the shutter 24 is opened to run the particles into the substance to be deposited, thereby forming a deposited film of the silver in a crystalline form on the surface of the substance to be deposited. The thus-formed deposited film of the crystalline silver has a metallic luster, i.e., a silver color. Furthermore, the surface of the deposited film is flat and its surface area is hence smallest.
In general, when a metal is contacting with the dermal tissue of the human body, a larger amount of the metal ion dissolves out in the skin as the contact surface becomes greater. Therefore, when following the conventionally-known method, the amount of the metal ion which dissolves out in the skin is extremely little and sterilizing and bacteriostatic action is also little correspondingly.